Definition of the factors controlling zein synthesis during maize endosperm development will increase our understanding of the mechanisms regulating storage protein synthesis in maize and other cereals and eventually lead to the development of cereals of improved nutritional quality. We propose to investigate: 1) The synthesis of zein mRNA during mutant endosperm development. Zein cDNA will be prepared and used as a probe to measure the synthesis of zein mRNA. 2) The changes of nonhistone chromosomal proteins and the properties of RNA polymerase II in maize mutants. Mutants such as opaque-2 have been shown to affect zein synthesis at the transcriptional level. Chromatin will be isolated and reconstituted, and transcribed in vitro by purified maize RNA polymerase II to measure regulation of zein synthesis. Nonhistone chromosomal proteins and their pattern of phosphorylation will also be examined. 3) The effect of nitrogen fertilizer on the synthesis of zein in maize endosperm. The production of zein mRNA under different rates of nitrogen fertilization will be measured using cDNA as a probe to determine the manner in which zein synthesis is altered. In vitro transcription of chromatin from plants grown at different rates of nitrogen fertilizer will be studied to determine the role of nitrogen fertilizer on alteration of nonhistone chromosomal proteins and zein synthesis.